Generally, the control moment gyroscope (CMG) refers to a motor applied apparatus equipped with a rotor of high moment of inertia, which is used to generate torques for the purpose of position stabilization and re-orientation of a vehicle or a floating platform such as satellite, ship, submarine, automobile, aircraft, missile, and so on.
Such control moment gyroscope is a torque generating actuator that uses the gyroscopic principle of the physics, and as illustrated in FIG. 1, it includes a flywheel 21, a spin motor 20, and a gimbal motor 10. Specifically, the flywheel 21 is mounted to a rotating axis of the spin motor 20, and the rotating axis of the gimbal motor 10 is disposed perpendicularly to the rotating axis of the spin motor 20. As the spin motor 20 rotates the flywheel 21 at high speed, momentum h is generated, and as the rotating axis of the spin motor 20 is rotated (g) about the rotating axis of the gimbal motor 10 by the driving of the gimbal motor 10, torque T is generated on an axis perpendicular to these two shafts.
Hereinbelow, the conventional control moment gyroscope is described in detail with reference to FIG. 1 again.
As illustrated in FIG. 1, the gimbal motor 10 is disposed extending to the left-hand side of the drawing, and a rotating and a rotating frame 11, in a shape extending to the right-hand side of the drawing, is mounted to a rotating shaft of the gimbal motor 10 and rotated. The spin motor 20 is mounted to the rotating frame 11, and the flywheel 21 is rotated by the spin motor 20. By the configuration as described above, the rotating frame 11 is rotated, as well as the flywheel 21 is rotated in an orthogonal direction, thus generating gyroscope torque.
However, the related control moment gyroscope as described above takes up a considerable space, because of the rotating frame 11 formed on the gimbal motor 10 and extending to the right-hand side of the drawing, and the flywheel 21 of the spin motor 20 disposed on the rotating frame 11. That is, considering the storage capacity of the satellite and limited space, the space for the control moment gyroscope and mass thereof has to be reduced with respect to the respectively given momentums and torques as much as possible, but the large volume of the related control moment gyroscope described above occupies a considerable space, thus making it a difficult candidate for an actuator of small satellite.
Further, because the rotating frame 11 has a shape of an open structure supporting a portion of the side surface of the spin motor 20, there are drawbacks concerning structural integrity, stability issue occurring due to micro-vibration generated from the motor driven, and unstable heat sink characteristic of the spin motor 20 generating high temperature heat.